Personne : Falci, Rodrigo Ferreira
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Université Laval. Centre d'optique, photonique et laser
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Publication Accès libreThe role of tungsten oxide in Er3+ -doped bismuth germanate glasses for optical amplifcation in L-band(Nature Publishing Group, 2023-05-31) Çamiçi, Hüseyin Can; Messaddeq, Younès; Guérineau, Théo; Rivera, V. A. G; Falci, Rodrigo Ferreira; LaRochelle, SophieA series of novel Er³+-doped bismuth-germanate glasses containing diferent tungsten concentrations with a molar composition of 97.5[(75 − x)GeO₂–25Bi₂O₃–(x)WO₃]–2Sb₂O₃–0.5Er₂O₃ (x = 5, 10, 15, 20, and 25 mol%) were fabricated. Their thermal properties are measured by diferential scanning calorimetry. A structural investigation by Raman spectroscopy suggested that changes occurred in the glass network by WO3 incorporation. By laser excitation at 980 nm, a strong emission from Er³+ ions at 1532 nm is observed, while the WO₃ addition caused changes in the emission spectra. The emission cross-section spectra of Er³+ are calculated by both McCumber and Füchtbauer–Ladenburg theories and their comparison showed these theories yielded slightly diferent results, but in both cases, the calculations showed that a gain signal in L-band can be achieved when 30% of the Er³+ ions are at the excited state. This study proves that the Er³+-doped bismuth-germanate glasses are suitable for ₂optical fber amplifer applications operating at C- and L-band. Publication Restriction temporaireNovel insights on energy transfer processes in [Ce4+/Ce3+]-Er3+-doped tellurite glass(Elsevier Ltd., 2022-10-14) Carvalho Pinto, Iago; Falci, Rodrigo Ferreira; Rivera, V. A. G; Guérineau, Théo; LaRochelle, Sophie; Messaddeq, YounèsPrevious works have been already reported on multiphonon-assisted non-resonant energy transfer in Ce3+-Er3+-doped tellurite glasses. However, it is not clear the mechanism of the radiative emission of Er3+ centered at 1530 nm. In this paper, we reported a better understanding of the mechanism of interactions between those two rare-earth ions via a systematic study. For that, we will explore the energy transitions between Ce4+/Ce3+ and Er3+ ions in a tungsten-tellurite glass to both emission (in the near infrared) and upconversion (in the visible) spectrum. Here, Ce4+ and Ce3+ were obtained in an Er3+-doped tellurite glasses via the addition of different concentrations of CeO2 as part of the composition of the samples. Emission spectrum, under a 980 nm excitation, giving rise to a series of interactions between Ce3+↔Er3+ resulting in: (i) a subtle increase of the Er3+ emission intensity in the near-infrared region for 0.1 mol% of CeO2, and then a decrease in the emission for higher CeO2 concentration in both cases without any significant increase in the bandwidth, and (ii) a decrease of the visible upconversion emission intensity with the addition of CeO2. Such interactions are achieved via a coupling yielding and energy transfer from both rare-earth ions.